Operation, Specifications | 8246-A Transmitter
Bulletin 8246-A Page 3
OPERATION
When the instrument is piped with impulse lines running from upstream and downstream sides of the orifice plate, process pressures from the respective lines are transmitted through an isolating diaphragm and silicone oil fill fluid to a sensing diaphragm in the center of the capsule. Capacitance plates on both sides of the sensing diaphragm detect the position of the diaphragm and convert the differential pressure into a 4-20 mA signal. The 8246-A communicates with the 8246-C Interface using standard frequency shift keying, a widely accepted communication technique. The Interface uses high frequency signals superimposed on the 4-20 mA transmitter output to communicate over the loop. Because the net energy added to the loop is small, communica tion dœs not disturb the 4-20 mA signal at all. The instrument can be re-ranged with or without the communicator. If the Interface unit is not available, range can be set with buttons located under the metal certification label. Range settings can take place on line provided an 8246-A-3M (3-valve, zeroing manifold) or 8246-A-5M (5-valve, zeroing and line blowdown manifold) are used to isolate the impulse lines from the process.
To order, specify: 8246-A Smart Pressure Transmitter with calibration range. 8246-A-3M Smart Pressure Transmitter with 3 valve manifold and calibration range. 8346-A-5M Smart Pressure Transmitter with 5 valve manifold and calibration range. Pressure tap size: ¼fpton2 1⁄8 " centers on flanges; ½ fpt on 2", 2 1⁄8 ", or 2¼" centers with adapters Electrical entrance size: ½ " fpt Total weight: 8.5 lb Isolating diaphragms and drain/vent valves: 316SS Process flanges and adapters: 316 SST Wetted O-Rings: Viton Fill fluid: Silicone oil Operates within specifications between static line pressures of 0.5 psia and 3626 psig Maximum differential: 3626 psi Supply voltage (external power supply required): 10.5 to 55 V dc with no load. Minimum resistance 250 ohm, 24 V dc nominal. Operating temperature: –40 to 185°F (–40 to 85°C) Storage temperature: –50 to 185°F (–46 to 85°C) Electronics housing: Low copper aluminum (NEMA 4X). Rated for FM explosion proof applications. Paint: Polyester-epoxy Mounting: Bracket is supplied for mounting to pipe up to 2" diameter and for panel mounting. NOTE: Transmitter can be mounted in any position.
SPECIFICATIONS Rangeability: 100:1 turndown Differential pressure range:
min. range: 0-2.5"w.c. max. range: 0-250"w.c. Output: 4-20 mA dc Accuracy: ±0.075% of calibrated linear span Temperature effect: ±0.0938% of span per 50°F change of span Damping time constant continuously adjustable from 0.36 seconds Power supply effect: Less than 0.005% of output span per volt
WARNING: Situations dangerous to personnel and property may exist with the operation and maintenance of any combustion equipment. The presence of fuels, oxidants, hot and cold combustion products, hot surfaces, electrical power in control and ignition circuits, etc., are inherent with any combustion application. Components in combustion systems may exceed 160°F (71°C) surface temperatures and present hot surface contact hazard. Fives North American Combustion, Inc. suggests the use of combustion systems that are in compliance with all Safety Codes, Standards, Regulations and Directives; and care in operation.
CONTACT fna.sales@fivesgroup.com T +1 800 626 3477 - F +1 216 373 4237
Fives North American Combustion, Inc. 4455 East 71st Street - Cleveland, OH 44105 - USA www.fivesgroup.com
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